1. Field of the Invention
The present invention relates to headers for combines. More particularly, it relates to headers having cutter bars that extend laterally across the width of the leading edge of the header.
2. Description of the Related Art
Headers are devices that are mounted to and across the front of agricultural combines to cut crop plants and direct them toward a crop-receiving opening of the combine for threshing, separating and cleaning inside the combine. Thereby, the header typically has a width that is significantly larger than the width of the crop-receiving opening of the combine. To this end, the header comprises a crop transporting mechanism to transport the crop towards the central crop-receiving opening of the combine.
Headers may use a reciprocating cutter bar or knife that is disposed across the leading edge of the header adjacent to the ground. The cutter bar severs the plant stalks close to the ground. A reel is also typically provided on these headers to control the tops of the plants. The reel pushes the top of the plant rearward, causing the plant to fall onto the header. The header transports the plant laterally toward a central portion of the header where there is a crop-receiving aperture. Once the crop passes through this aperture it is received in a crop-receiving aperture of the combine, which further conveys the plant back rearward into the combine for further processing.
There are two common types of headers, wherein each type of header applies a different technique to transport the crop laterally. The first of these is called an “auger platform” or “auger header”. An auger header comprises an auger in the form of a helical screw that extends laterally across the width of the header. The auger is mounted for rotation at a rear end of the header directly above a floor surface of the header frame. In operation, crop plants fall onto the header directly in front of, or somewhat against the auger. Thereby, the crop plants get caught between the auger and the floor surface so that, due to the rotation of the auger, the crop plants are laterally transported towards the crop-receiving aperture.
The second type of header is called a “draper platform” or “draper header”. A draper header has no auger located at the rear of the header. The floor surface of the header is instead formed by two generally flat endless loop conveyor belts mounted to move the crop in the lateral direction to the middle of the header. The conveyor belts are typically located immediately behind the cutter bar and take the place of the floor and the auger of the auger header. A central conveyor is located between these two conveyors to receive the cut crop material and convey it rearward into the crop-receiving aperture.